[NAN] Consolidate publish/subscribe callback sets into single set

Merge onPublishFail & onSubscribeFail into onSessionConfigFail.
Merge onPublishTerminated & onSubscribeTerminated into onSessionTerminated.
A session is either publish or subscribe (never the two) so redundant.

(cherry-pick of 8414f5cf)

Bug: 27610709
Change-Id: I0282d17db88754428da25ee5f064b9a4805f9736
(cherry picked from commit 776ba56e)